Stumping for fellow Democrat Hillary Clinton, his former secretary of state, President Obama called her Republican rival Donald Trump a "con artist," temperamentally unfit to be president. Obama also criticized FBI chief James Comey for reviving the issue of Clinton's emails in what could be interpreted as an attempt to influence the election. Trump, for his part, vowed to repeal Obama's signature health care system as soon as he became president. Zlatica Hoke has more.